1881.] NATURAL SCIENCES OP PHILADELPHIA. 35 



camp was located. Three entire days, besides other portions of 

 time, were spent in this work by myself and assistant. The nest 

 interior sloped eastward, and toward the base of the hill, and 

 occupied a space (in round numbers) eight feet long, three feet 

 high and one and one-half feet wide, the whole tunneled through 

 the soft red sandstone rock of which the ridge consists. This 

 rock is much of it quite friable, crumbling readily under the pres- 

 sure of the hand, but packs tightly under the stroke of mallet and 

 chisel, thus making difficult mining for men if not for ants. Most 

 of our work was done with the chisel, and the galleries and rooms 

 had to be worked out with knives. ^ These thirty-six cubic feet of 

 rock were fairly honeycombed by the series of galleries and cham- 

 bers above referred to. 



The dimensions of the exterior nest are as follows (see PI. IV, 

 fig. 15): Height, north side, 2i inches; west side. If inches; 

 east side. If inches; south side, 1| inches; distance across the 

 top, a e = 10 inches; distance around the base, a ^■ e c = 29 

 inches ; distance around the crater, m o n r = S inches ; eastern 

 ridge of the crater, v n = 1|- inches ; western ridge of crater, 

 m s =: ^ inch ; distance across the gate at a; 2 = 1 inch, at s v = f 

 inch ; depth of the gate before bending, 4 inches. The mouth, as 

 appears from measurement, was ovate (PI. IV, fig. 14), but the 

 entrance beyond was a circular tube. 



The mound was removed and the soil carefully scraped away. 

 Close to the surface, at the distance of one-half to three-fourths 

 of an inch, openings were found of various sizes, from one-fourth 

 to one inch in diameter. These openings occurred at various dis- 

 tances from the gate, on all sides, four and one-half, five, five and 

 one-half, eight, eight and one-half inches and upwards to ten inches 

 on the northwest side, eighteen inches on the south side, and 

 eighty-two inches on the southeast, in which direction the formi- 

 cary extended. Toward the termination of the nest, however, 

 thej' did not appear so near to the surface. 



Section views were next had by cutting across the nest. On 

 the north side I found no galleries at a greater depth than eight 

 inches. On the south side, the first cutting was made east and 



^ While engaged upon this part of my work, I was pleasantly surprised 

 by a brief visit of Prof. A. ?, Packard. I am glad to be able thus to refer 

 to his valuable testimony in confirmation of some of the statements of this 

 paper. 



